Berean Literal Bible
2 For if the word having been spoken by angels was unalterable, and every transgression and disobedience received a just recompense, 3how shall we escape, having neglected such a great salvation, which, having received a commencement [i.e., first] declared by the Lord, was confirmed
This is the main verb:
Verb - Aorist Indicative Passive - 3rd Person Singular
Strong's 950: To confirm, ratify, secure, establish; pass: I guarantee. From bebaios; to stabilitate.
to us by those having heard, 4 God bearing
Verb - Present Participle Active - Genitive Masculine Singular
Strong's 4901: To unite in bearing witness, sanction. From sun and epimartureo; to testify further jointly, i.e. Unite in adding evidence.
This present participle must be read with respect to the main verb's aorist.
witness with them both by signs and wonders, and by various miracles and distributions of the Holy Spirit, according to His will.
The confirmation was in the aorist past and the bearing is associated with that aorist past.
Does the use of past tense in Hebrews 2:4 indicate that signs, wonders, miracles and the gifts of the Holy Spirit had ceased?
No, not necessarily, just because it is in the past, it does not necessarily imply that it does not carry to the present or the future.
OP: the use of past tense indicate that signs, wonders, miracles and gifts of the Holy Spirit were something from the past, useful at some point to authenticate the preaching of the gospel
Right, especially at that time.
What is the implication today?
Today, we can read these signs, wonders, miracles and gifts of the Holy Spirit from the gospel texts, so that we can believe in the great salvation on faith.
We should not demand a repetition of these signs to believe.
26A week later his disciples were in the house again, and Thomas was with them. Though the doors were locked, Jesus came and stood among them and said, “Peace be with you!” 27Then he said to Thomas, “Put your finger here; see my hands. Reach out your hand and put it into my side. Stop doubting and believe.”
28Thomas said to him, “My Lord and my God!”
29Then Jesus told him, “Because you have seen me, you have believed; blessed are those who have not seen and yet have believed.”
Does this mean no more signs and wonders today?
No, not at all. It only means that signs and wonders had attested Jesus' great salvation work back then. We should not demand a re-run of the same.